The story got widespread attention. Based on CT scans, North Carolina state palaeontologist Dale Russell had reported in Science (vol 288, p 503) that the rock was the remains of a heart. Dinosaur metabolism was a hot topic at the time, and the "heart's" structure led him to conclude the dinosaur had an active metabolism, unlike cold-blooded reptiles.

Russell has since retired, and Tim Cleland of North Carolina State University in Raleigh and colleagues has re-examined the evidence. Cleland, who has been studying the preservation of soft tissues, used higher-resolution CT scans and other instruments to re-examine the supposed heart - and found it was mostly sand that had washed into the dinosaur's body after its death.

The researchers say that the sand appears to have preserved "small patches of cell-like microstructures". Could those be another example of the rare preservation of soft tissue? Perhaps, they say, but checking that out is another research project that might yield another paper.